The Chinese-originated belief that the environment gives energy that you can use to your own being. Not just a belief; it actually is real.

There is actually a whole LOT to feng shui, but you should look it up on your own. Lemme give you some examples:
Take for example, a mansion. Let's say you have a mansion and it is very-well decorated. Your feng shui would be great because you feel at great leisure because of the cleanliness & well-designed room of your own.
An example of negative feng shui would be if you live in a house that is not apt to your tastes, and is possibly filled with trash, or perhaps even an enormous pig-sty. This negative feng shui will possibly foster laziness, and even psychological results such as negative emotions, doubt, etc.

Feng shui deals not only with your personal shelter, but also the environment in general.

Most unfortunately, feng shui has been perverted into a drug-related symbol thanks to the hippies, along with the yin-yang (which basically represents good & evil in us all). In otherwords, when you speak of feng shui to the general public, you're probably going to be prejudged as a nut-job. Sad really.
Hippies need to realize completely what yin-yang and feng shui mean. THEY ARE NOT DRUG SYMBOLS. They are philosophical symbols that originated from ancient China, and these symbols have deep backgrounds that is worth researching.

"My house is a pig-sty so my feng shui is horrible. But sometimes, you make do. If you want better feng shui if you're in a pig-sty house, go outside and go for a walk. Just make sure you don't get too addicted to the freedom out there, or else you'll never want to go back to your pig-sty home. That's how I am."
-me